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PULMONARY FUNCTION TEST

Indications Clinical Practice Spirometry Comparinson Studies

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Indications

1. Diagnosis

2. Monitoring

3. Evaluation of disability or impairment

4. Public healthN Engl J med 331:25,1994

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Indications

Diagnosis To evaluate symtoms, signs , and abnormal results

of laboratory tests. To measure the effect of disease on pulmonary

function. To screen persons at risk for pulmonary disease To assess preoperative risk. To assess prognosis.

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Indications

Monitoring To assess effectiveness of therapeutic

interventions (eg. Bronchodilator therapy) To provide information on the course of diseases

affecting lung function. (eg.COPD and NMD) To assess current status of persons with

occupational exposure to injurious substances. To detect adverse reactions to drugs.

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Indications

Evaluation of disability or impairment To assess patients as part of a rehabilitation

program. To assess risks for an insurance evaluation. To assess the condition of persons for legal

reasons.

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Indications

Public health Epidemiologic surveys.

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Clinical Practice

1. Screening spirometry.

2. Lung volume calculation.

3. Classification of abnormal disease.

4. Interpretation.

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Screening spirometry

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Screening spirometry

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Screening spirometry

Procedure   

A full inspiration to TLC, then

A rapid, forceful maximal expiration to RV by spirometer.

At least three acceptable and two reproducible maneuvers .(FEV1 /FVC within 0.2 liter and PEF within 10%)

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Screening spirometryVolume-time spirogram

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Screening spirometry

Flow volume curve

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Screening spirometry

A : a hesitating start.

B : poor peak flow effort.

C : coughing

D : quit too soon.

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Screening spirometry

Calculations Forced vital capacity (FVC) FEV1 FEV1/FVC ratio FEF 25-75% (maximal mid-expiratory flow rate) PEF (peak expiratory flow )

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Lung volume calculation

Determinig FRC TLC closed-circuit helium method open-circuit nitrogen washout method  total-body plethysmography     

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Lung volume calculationclosed-circuit helium method

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Lung volume calculationclosed-circuit helium method

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Lung volume calculationopen-circuit nitrogen washout method

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Lung volume calculationtotal-body plethysmography

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Lung volume calculationtotal-body plethysmography

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Classification of abnormal diseases

1. Obstructive pulmonary disease

2. Restrictive pulmonary disease Intrapulmonic Extrapulmonic : thoracic, abdominal,

NMD, respiratory center depression.

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Classification of abnormal diseases

A:normal

B:severe COPD

C:mod.Restriction

D:a fixed upper airway obs.

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Interpretation (1)

FEV1/FVC < 70% : obstructive

Severity : (FEV1/FVC % ) FEV1 % pred method

          Normal > 70% >80%

          Mild 60-70 % 50% - 80%

          Moderate 45-60 % 30%- 50%

          Severe < 45% <30%

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Interpretation (2)

FEV1 / FVC > 70% FEF 25-75% / FVC < 65%

: mild obstructive lung disease. FVC < 80% pred

: imply restrictive lung disease.

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Interpretation (3)

FVC < 80% pred (TLC)

         Normal : TLC >81 % pred

          Mild : TLC 66-80% pred

          Moderate : TLC 51-65% pred

          Severe : TLC <50% pred

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Interpretation (4)

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Interpretation (4)2

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Interpretation (4)3

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Interpretation (4)4

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Interpretation (4)5

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Interpretation (4)

Abnormal gas transfer (% pred method )

         Normal : 81-140 %

         Mild reduction : 61-80 %

         Moderate : 41-60 %

         Severe : < 41 %

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Spirometry comparison study

Bronchodilator testProvocation test

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Spirometry comparison study

Bronchodilator test

:20% and 200ml improvement of FEV1 / FVC

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Spirometry comparison study

Provocation test

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Spirometry comparison study

Provocation test

:methacoline test PC20 < 25mg